The development of modern methods of clinical diagnostics and physiological control of the condition of human health, combining in itself express-effect, simplicity and high self-descriptiveness is one of the typical problems facing contemporary physiology, medicine and medical instrument making.
Present day Western medicine makes use of diversified instrumental methods involving tonometers, cardiographs, sphygmographs, plethysmographs and the like to conduct a special study of a particular feature of the cardiovascular system functioning, namely, evaluation or pressure changes in the blood flow, the condition of vessels' walls, and various hemodynamic parameters.
Oriental medicine, in turn, regards the pulse study as a universal method of diagnostics. Pulse diagnostics has been considered as the "kernel" of Oriental medicine and represented a sophisticated and subtle method for assessing the functional condition of practically every organ and system in the human organism. Figuratively speaking, the radial artery in the wrist zone is viewed by an oriental doctor as the focus and resonator where various physiological processes in the organism manifest themselves most vividly. The entire complex of sensations when palpating the pulse carries information about the condition of functional systems, the type and character of disorders, and the prognosis as regards the course of a disease.
Until recently, however, mastering the technique of pulse diagnostics has been fairly difficult owing to the duration (15 to 20 years) and difficulty of instruction, requiring a pulse diagnostician to have specially sensitive fingers, as well as the impossibility of acquiring objective information received from the pulse for collation and analysis.
In this connection, it has become necessary to develop devices permitting pulse diagnostics to be made more objective and teaching pulse diagnostics methods to be made easier.
One of the basic elements of pulse diagnostic devices is a pulse wave sensor, serving to convert different kinds of energy, e.g., mechanical energy of a pulse beat to an electrical signal. All major types of pulse wave sensors, namely, capacitive, tensometric, optical, piezoelectric, transform mechanical oscillations of the radial artery, which are the basic carrier of information, to an electric signal.
In Oriental medicine the pulse was studied in several positions, namely, in the wrist zone, on the radial and ulnar arteries, in the region of malleoluses, in carotids, in the lubital region, etc. But it is the wrist zone on the carotid in the area of the styloid process that was considered the main place for diagnostics. This place was regarded as the one connecting all canals and vessels of the body. But arranged close to the carotid are the venous and lymphatic vessels, the nerve trunk, as well as the meridian of the lungs, according to the teaching of Oriental medicine about the meridians. The condition of adjacent tissues also affects the pulse perception. Besides, according to the contemporary biophysics, the wave comprises the processes different by nature, namely, the movement of blood along a vessel, mechanical peristalsis wave running along the vessel, a sound wave formed from an impact during a systolic blood ejection from the heart to the blood channel and, in the final analysis, an electromagnetic wave. Each of these processes has its flow speed and its own character of action. Thus, in the place of the pulse wave collection there is formed a complex conglomerate of various processes both in the carotid per se and the effects on the part of adjacent vessels, namely, venous, lymphatic and nerve trunks. An experienced pulse diagnostician perceives not only general parameters in the form of frequency, strength and rhythmicity, fullness of the pulse, but also "burning", "prick", "hardening", "vibration" and the like, characterizing, in addition to the level and character of functional processes, the presence of inflammation, spasms or lithogeny, respectively. Hence, the physician's fingers, trained over dozens of years, serving as supersensitive biological sensors, perceive not only mechanical oscillations of the wall of the radial artery stipulated by its deformation caused by the blood pressure pulse, but also other finer and more subtle wave processes.
In this connection, there arises a problem of measuring the pulse wave, conditioned by the necessity of obtaining complete information about the processes in the section of the radial artery in the place of measurement, and correct interpretation of a pulse wave signal to make the diagnosis. The aforementioned sensors of the pulse wave have their own technical characteristics and, in particular, an amplitude-frequency response, stipulating the shape of a pulse wave signal. However, the amplitude-frequency responses of these sensors are such that as the pulse wave is measured, the pulse wave signal does not fully reflect all the processes at the section of measurement.
Closest to the invention claimed is a pulse-diagnostic device (U.S. Pat. No. 4,066,066), comprising, at least, one pulse wave sensor mounted on the inside of the wrist in the Cyn, Gyan and Chi points reflecting the condition of the internal organs and systems, a unit for processing the pulse wave signals, which processes n-sets of the pulse wave signal connected to the pulse wave sensor, and a register whose input is connected to the output of the pulse wave signal processing unit.
In said pulse diagnostic device the pulse waves are measured simultaneously by three pulse wave sensors secured on the patient's wrists. The force of pressing the pulse wave sensors is regulated by means of a vacuum cuff encompassing the wrist at the section of the pulse wave sensor arrangement.
An amplifier is used as a unit to process the pulse wave signals. From each pulse wave sensor an amplified signal enters the ammeter end/or register.
In U.S. Pat. No. 4,066,066, piezoelectric microphones serve as pulse wave sensors converting mechanical oscillations stipulated mostly by the deformation of the radial artery at the sections of measurement, caused by the blood pressure pulse. However, as was noted above, the pulse wave is a far more complicated phenomenon than only mechanical oscillations of the radial artery: it is a combination of all wave processes from slow, namely, the blood flow and the peristaltic wave, up to rapid, including sonic and electromagnetic ones. Thus, as the pulse wave is measured, the piezoelectric microphone perceives only part of the information about the pulse which is due to the amplitude-frequency response of the piezoelectric microphone and this is reflected also in the shape of the pulse wave signal.
The pulse-diagnostic device being described is a sphygmograph intended to be used in practice based on the methods of Chinese medicine. Analysis of the pulse wave signals, which in actual fact are only amplified and then registered, is made by the doctor visually. The analysis is carried out with due regard for the amplitude (beat strength) characterizing the pulse as pulses magnus or pulses parvus, for the frequency of beats, characterizing the pulse as swift of slow pulse, and for rhythmicity, characterizing the pulse as rapid (non-rhythmic) or equal (rhythmic).
The pulse is regarded as a single information field and, depending on the depth of maximum amplitude, can be surface, i.e., "bright", "active", deep, i.e., "small", "weak", perceived only upon fully pressing the wrist, and intermediate between the first two.
The Cyn, Gyan, Chi points in which measurement is taken from the radial artery on the wrist, show the character of disturbance, namely, in the Cyn region--from head to chest, in the Gyan region--from the diaphragm to the navel, and in the Chi region--from the navel to the feet.
The pulses are referenced to the specific organs by virtue of empirically derived criteria. For instance, as to the heart and lungs, referred to the Yang point, a prolonged and active is referred to the heart, and brief and slow pulse--to the lungs.
For the liver and kidneys related to the Yin point, a long pulse relates to the kidneys and a short and soft pulse--to the liver. It is said that the spleen pulse occupies an intermediate position and is diagnosed with difficulty.
Solution of the problem of locating the place of a disease is interpreted as follows: a rapid pulse corresponds to the Yan region (six hollow organs), and a slow pulse--to the Yin region (five dense organs).
Using the above-identified criteria, one singles out the basic types of pathological pulses in the classical Chinese medicine: a tense pulse, large pulse, small pulse: high spirit, but little blood, small pulse: "little spirit and blood", abrupt pulse: "Yah thrives, Yin is absent", soft pulse: "Yin thrives, Yan is absent".
In view of the foregoing, one can draw the following conclusions. In the said method the surface and deep pulses, taken in one pulse position, are not differentiated as the pulses related to different organs, namely, hollow (Yan) and dense (Yin), respectively. The pulse wave is analyzed as regards the strength, rate and rhythmicity or beats, and the shape of the pulse wave signal is not analyzed.
The above-described interpretation of pulses performed by a doctor visually rules out automation in obtaining the diagnostic conclusions and collation of the data obtained, as well as it makes the diagnosis more subjective and the training of a doctor becomes difficult.
The method of measuring a pulse wave by means of said pulse diagnostic device consists in the fact that the pulse wave sensor is pressed to the wrists in the Cyn, Gyan, Chi points, regulating the pressure force with the aid of a vacuum cuff. Since the pulse wave is measured in said three points at a time and the force of pressing the piezoelectric microphones to the patient's wrist is set practically equal, it is fairly probable that the measurement in an adjacent point affects that of a pulse wave in each of said points, thus impairing the authenticity of information. Besides, as the pulse wave is measured simultaneously in three points, it is impossible to control the position of piezoelectric microphones to obtain reliable information about the surface and deep pulses.